// unordered_map::erase
#include <bits/stdc++.h>
using namespace std;
int main ()
{
    unordered_map<string,string> mymap;

    // populating container:
    mymap["U.S."] = "Washington";
    mymap["U.K."] = "London";
    mymap["France"] = "Paris";
    mymap["Russia"] = "Moscow";
    mymap["China"] = "Beijing";
    mymap["Germany"] = "Berlin";
    mymap["Japan"] = "Tokyo";

    // erase examples:
    mymap.erase ( mymap.begin() );      // erasing by iterator
    mymap.erase ("France");             // erasing by key
    mymap.erase ( mymap.find("China"), mymap.end() ); // erasing by range

    // show content:
    for (auto& x: mymap )
        cout << x.first << ": " << x.second << "\n";
    return 0;
}

